Archived user: A user that is not active, but the admin can retain user data and history. In this case, there is the possibility to quickly reinstate the user in the future.
Deleted user: A user is not active, and there is no interest in keeping his data and history. Once a user is deleted, reinstating it will not be possible.
You can learn how to add and remove users in this article. How do I add and remove a user?